Organizational environment

The Office of Highway Policy Information (HPPI) has developed the VTRIS W-Table web site. It is available to all the public. The HPPI analytical team representative, David L. Jones, can be reached at (202) 366-5053.

System Availability

VTRIS W Reports are available:

Monday- Friday: 7 a.m. To 10 p.m. (EST)

Sunday: 12 Noon To 10 p.m. (EST)

Reports Subsystem

The VTRIS W-Tables are designed to provide a standard format for presenting the outcome of the Vehicle Weighing and Classification efforts at truck weigh sites. The data that appears in the W-Tables comes from the Summary files that are generated by the Summary subsystem.

VTRIS W-2 Table

This table displays a Summary of the Vehicle Counted and the Vehicle Weighed for selected stations by Vehicle Classification. The Vehicle Classification data is averaged for each hour and the 24 hourly averages are added for the average daily count. The W-2 Table breaks the data down by the 13 Vehicle type categories. But this table considers weight information for Vehicle type 5 through 13.

VTRIS W-3 Table

This table contains information on the Average Weights of Empty, Loaded and all Trucks and their Estimated Average Carried Load. This information is broken down by Vehicle Classification 5 through 13 for each Station location. This process uses weight measurements and the set of breakpoints between empty and loaded trucks to calculate Percent Load, Percent Empty, Average Load Weight and Average Empty Weight.

VTRIS W-4 Table

This process is most commonly used in Pavement design since it contains information on Truck Axle loadings and their effect on Flexible and Rigid Pavement based on 18-KIP Equivalent Axle Load. This process builds three different sections:

I) Equivalency Factors provides the Number of Single, Tandem, Tridem and Quad axles weighed which fall into particular weight ranges and gives the resulting 18-KIP Equivalent Axle Loads on the two type of Pavement

II) Equivalency Summary contains information on the Summary ESAL (Equivalent Single Axle Load) Design Factors such as ESAL per Vehicle, Percent Distribution for Flexible and Rigid Pavements and Truck percent.

III) 20 Year ESAL Estimates displays Flexible and Rigid pavements Growth Rates for percent Truck. For all sections, information is grouped by Truck type 3 through 13 and can be shown for selected station(s), location(s) and/or highway Functional Classification(s).

User defines the Ranges of Axle Load in 18-KIP for four types of axles. The default for parameters are:

Single Axle

Starting: 1.0

Interval: 1.0

Ending : 20.0

Tandem Axle

Starting: 2.0

Interval: 2.0

Ending : 40.0

Tridem Axle

Starting: 3.0

Interval: 3.0

Ending : 60.0

Quad Axle

Starting: 4.0

Interval: 4.0

Ending : 80.0

Those ranges are to be used in calculation of the Equivalent Single Axle Load (ESAL) coefficients for Flexible and Rigid surfaces. The following expressions determine special coefficients depending on Axle Load in KIPs (X) and type of Axles (Y) where Y can be 1 (Single), 2 (Tandem), 3 (Tridem) or 4 (Quad)

VTRIS W-5 Table

This table shows the Number of Trucks Weighed in various Gross Weight ranges, Total Average Vehicles Weighed and Total Average Vehicles Counted. This process produces values for Truck types 3 through 13 and shows for selected station(s) and/or Functional Classification(s) of highway. User defines the Ranges of Gross Weight. The default for parameters are :

Starting Value: 5

Interval: 2

VTRIS W-6 Table

This table gives the Number and Percent of Vehicle by type exceeding a User specified Axle, Tandem and Gross Weight Limit (i.e. all Violations of the Bridge Formula). A vehicle may have multiple violations of the set criteria. The information can be shown by station(s) and /or Functional Classification(s) of highway and is broken down by Vehicle type 3 trough 13. The User assigns the Limit Value Axle Weight range for Single, Tandem, Tridem and Quad Axles and Gross Weight. The default for parameters are:

Single : 9070

Tandem: 15420

Tridem: 0

Quad: 0

Gross: 36290

The Number Exceed and the Percent Exceed are calculated for each Axle Type and Gross Weight. For the Number Exceed to sum up the number of axles of each type (Single, Tandem, Tridem, Quad and Gross) from the limit value to the maximum number of weight interval. This table includes the Violations of the Bridge Gross Weight Formula depending only on Vehicle type. The Bridge Gross Weight Formula provides a standard to control the spacing of Truck axles on the Vehicle that uses highway bridge. The Number of Violations of the Bridge Gross Weight Formula calculated previously are in the Summary process.

VTRIS W-7 Table

This table gives the Number and Percent of Average Daily Count for those measurements where Axle Load above a Limit. The Gross Weight Limits by Vehicle Class (in Kilograms) was assigned by the User. The default is equal to: VT_Limit[j] = {18140, 24490, 33570, 33570, 36290, 36290, 36290, 36290, 36290 } where j = 5, 13 for each vehicle type respectively.

The information can be shown for each station(s) and/or Functional Classification(s) of highway broken down by Vehicle types 5 through 13.

The Numbers and Percentage shown under the "In Excess" column are the vehicles that are classified as overweight in their respective Axle groupings. Numbers under the "Not in Excess" column plus the "In Excess" column should add to the "Number Weighted/Avg. Daily Count". For further information about the VTRIS W-Table Reports and the VTRIS (Vehicle Travel Information System) software. Go to http://www.fhwa.dot.gov/ohim/ohimvtis.htm and download the VTRIS User Guide.